1. Field of the Invention
The present invention relates to an electronic device designed to incapacitate a person by means of non-lethal electric shock. More particularly, the present invention relates to a hand-held stun gun used by law enforcement officers to affect the neuromuscular system of the body by interrupting electrical nerve impulses, causing a mild state of confusion or disorientation.
2. Description of the Prior Art
In general, the term "stun gun" has been generically applied to any electronic device designed to incapacitate a person by means of non-lethal technology. Most stun guns have a hardened and nonconductive exterior case in which is housed the electronic circuitry. Generally protruding from the case are preferably two or four probes through which a high voltage, low duration, and low charge pulse, produced by the internal circuitry, is delivered. An example of such a device is disclosed in U.S. Pat. No. 4,872,084 issued to Dunning, et al. for "Enhanced Electrical Shocking Device with Improved Long Life and Increased Power Circuitry" ("'084 Patent").
The disclosure in the '084 Patent describes a stun gun which utilizes a pair of surge arresters in place of the conventional internal spark gap found in most stun guns. The pair of surge arresters are used to eliminate the problems associated with the corrosion and pitting of the internal spark gap which made prior art stun guns unreliable. Also disclosed in the '084 Patent is a strap attached to the stun gun housing such that when in use, the user's fingers are wrapped around grooves in the housing and the strap is wrapped around the back of the user's hand. If the stun gun is knocked out of the user's hand by an assailant, the force of the stun gun "flying out of the user's hand" creates a pulling effect on a pin connected from the strap to an ON-OFF switch, causing the switch to open and break contact, thereby deactivating the stun gun temporarily. Reinsertion of the strap end back into the stun gun housing serves to reactivate the device.
The electronic circuitry within the housing of the '084 Patent utilizes an inverter transformer and an output transformer to generate the high voltage at the contact probes. The inverter transformer is driven by a standard relaxation oscillator circuit which is activated upon closure of a trigger switch. The secondary winding of the inverter transformer is used to drive a half wave rectifier circuit to charge a large storage capacitor. The storage capacitor continues to charge until a point when the voltage across a series pair of surge arresters reaches a "breakover" point, at which time the storage capacitor discharges through the primary windings of the output transformer. The output transformer, having a turns ratio selected to step up the applied voltage, produces approximately 75,000 volts across the contact probes attached to the secondary winding. The circuit thus operates to produce the high voltage for so long as the trigger switch is operated.
Therefore, there exists a need for a stun gun device having a low battery indicator light to alert an operator that the battery driving the internal electronic circuits have reached the end of their useful life. Further, the market demands a stun gun having a fail-safe shutdown feature wherein an overzealous operator is precluded from applying the device against a victim for prolonged periods. The market further demands a stun gun which is deactivated if stripped away from an officer and which is rendered useless to an assailant who may obtain possession of the device without a reactivation component securely strapped about the operators wrist or to his person. Lastly, the market demands the efficient utilization of energy stored in the battery power source to permit the device to be used for prolonged periods.